Space suit heat exchanger with liquid boiling point control



E. H. BRISSON ET AL SPACE SUIT HEAT EXCHANGER WITH LIQUID BOILING POINT CONTROL 5 Sheets-Sheet 1 Sept. 26, 1967 Filed Aug. 27, 1964 Spt. 26, 1967 E H, BRISSON ETAL v 3,343,536

SPACE SUIT HEAT EXCHANGER WITH LIQUID BOILING POINT CONTROL Filed Aug. 27, 1964 3 Sheets-Sheet 2 FICLB lNVENTORS EDGAR H- BRISSON KENNETH L..- HOWER ByVal/n (MP-l #dA/@M65 ATTORNEY Sept 26, 1957 E. H. BRlssoN ETAL 3,343,536

SPACE. SUIT HEAT EXCHANGER WITH LIQUID BOILING POINT CONTROL Filed Aug. 27, 1964 3 Sheets-Sheet 3 di f f W sg w /Z f gz 4 .Y fd z j@ E /za/l f-l 3- 7 AW /z INVENTORS EDGAR I-i- BRISSON KENNETH L HOWER ATTORNEY United States Patent ce Patented Sept. 26, 1 967 3,343,536 SPACE SUIT HEAT EXCHANGER WITH LIQUID BOILING POINT CONTROL Edgar H. Brisson, Hazardville, Conn., and Kenneth L.

Hower, Longmeadow, Mass., assgnors to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Filed Aug. 27, 1964, Ser. No. 392,402 Claims. (Cl. 12S-142.5)

This invention relates to pressurized suits, such as space suits, and more particularly to the method and apparatus of regulating the temperature of the uid, such as air or oxygen, being supplied the space suit occupant. The invention described herein was made in the performance of work under a NASA contract and is subject to the provisions of the National Aeronautics and Space Act of 1958, Public Law 85-568 (72 Stat. 426; 42 U.S.C. 2451), as amended.

As the activity of the space suit occupant varies, the metabolic heat load from the space suit occupant can vary between 1600 to 400 B.t.u./ hour. It is therefore necessary to control the temperature of the fluid being provided to pressurize the space suit and to permit the occupant to breathe so that the iiuid being provided the space suit does not dier drastically in temperature from the body temperature of the space suit occupant.

It is an object of this invention to control the temperature of the iluid being provided to a pressure suit.

It is a further object of this invention to control the temperature of the uid being provided to a pressure suit utilizing a water boiler heat exchanger comprising controlling the temperature of the air being provided to the occupant by controlling the pressure within the water boiler and hence controlling the saturation temperature and pressure of the water and thereby the boiling point of the water in the heat exchanger.

Other objects and advantages will be apparent from the specification and claims and `from the accompanying drawings which illustrate an embodiment of the invention.

FiG. 1 is a showing of a pressurized suit, such as a space suit, with occupant carrying a lite support system.

FIG. 2 is a simplified schematic of the pressurized suit life support system.

FIG. 3 is a front view of the water boiler (liquid-gas) heat exchanger of the life support system.

FIG. 4 is a side view of the heat exchanger of the life support system.

FIG. 5 is similar to FIG. 4 but is a cross-sectional showing of the heat exchanger of the life support system.

FIG. 6 is a showing of the closure member which is part of the heat exchanger and which envelops the thermal bulb.

FIG. 7 is a showing of the wick sensor which is positioned between the closure members shown in FIG. 6 and which also envelops the thermal bulb of the heat exchanger.

FIG. 8 is a cross-sectional showing through steam outlet valve showing its cooperation with the thermal bulb.

Referring to FIG. 1, we see pressure suit 10 which may be a space suit or other type of pressure suit and which comprises basically a helmet or head closure 12, pressurized suit body 14, including gloves 16 and boots 18, and portable life support system 20.

Referring to FIG. 2 we see a simplified schematic of the pressurized suit life support system 20 comprising pressurized Ventilating fluid reservoir 22, which is preferably a gaseous oxygen (O2) reservoir and which is connected through shutoff valve 24 and regulator valve 26 to supply line 28, maintaining the pressure level of the gas in the system. Recirculating oxygen gas passes through line 28 and into space suit 10 and then to the extremities of the body of the occupant through an intake supply system and then therefrom through an exhaust system to exhaust line 30. In passing over the body of the space suit occupant, the gas controls body temperature and absorbs perspiration. After passing through the C02 remover 32 and vblower 34, the recirculating gas is passed through water boiler heat sink 36 where cooling of gas and condensation of water vapor occurs, then through water separator 38 where condensed water removal occurs and then through line 40 to rejoin the supply line 28.

Referring to FIG. 3 we see water boiler heat exchanger 36 in a front view with the water reservoir 42 showing in the plane of the paper. A predetermined amount of water is admitted to water reservoir 42 through water charging port 44. Steam is generated and escapes from the Water boiler core 56 through steam outlet valve 46. The lluid, such as air or oxygen with perspiration vapor therewith, which has passed through the pressure suit and has passed into life support system 20 through line 30 enters heat exchanger 36 through duct 48. The condensed water and gas (air or oxygen) leaves heat exchanger 36 through duct S0 and enters the water separator 38. In the Water separator 38 the water is separated from the gas and while the gas passes through duct 40, the separated water passes to heat exchanger 36 through line 52.

Referring to FIG. 4 we see a side View of heat exchanger 36 and it will be noted that heat exchanger 36 is basically a sealed vessel contained within wall S4 and including three sections, namely, Water reservoir section 42, heat exchanger core section 56 and steam exit header 58.

Referring to FIG. 5 we see a cross-sectional showing of heat exchanger 36 including wall 54, Water reservoir section 42, heat exchanger core section 56 and steam exit header 58. Air or oxygen from duct 48 (FIG. 3) enters sealed chambers 60, 62, 64 and 66 through a conventional header (not shown) and passes through these chambers following the paths defined by corrugated sheets such as 68 positioned between top and bottom plate members 7l? and 72. Pressure members 60' through 66 are sealed at their ends by closure channels such as 74 and 76. The oxygen passages or closure members 60 through 66 are of a sealed, sandwich construction and constitute the gas, oxygen or air side of the heat exchanger and present parallel passages such as 78 and 80 which run the length of the heat exchanger between headers which communicate with inlet duct 48 and outlet duct 50 (FIG. 3). The gas, such as air or oxygen, which has passed through space suit 10, is passed for temperature control purposes through passages 7,8 and 80 of heat exchanger 36. Elements 60 through 86 comprise the gas side or unit 82 of the heat exchanger 36.

The water side or unit 84 of heat exchanger 36 includes water reservoir section 42, sections 86, 88, 92 and 94, which are positioned alternately with sections 6l) through 66 of the gas side 82 of heat exchanger 36, and also includes steam header 58, which connects to steam outlet valve 46 (FIGS. =3 and 4) and sections 42 and 86 through 94. Water reservoir 42 and sections 86 through 94 are lled -with wicking material such as Refrasil B-100 which becomes saturated with the water introduced to Water reservoir through water charging port 44 (FIGS. 3 and 4). Due to the capillary action of the water within the wicking material in sections 42 and l86 through 94, the water is placed in immediate contact with the plate members, such as 70 and 72, and closure members 7-4 and 76 of the gas enclosure members 60 and 66, thereby producing maximum heat transfer results.

It is the object of this invention to control the boiling point of the liquid on the liquid side 84 of heat exchanger 36 so as to control the temperature gradient between the liquid side 84 and the air side 82 of heat exchanger 36 and thereby control the temperature of the gas being passed through the gas side unit 82.

While the boiling point of water on the earth sunface is 2li2 F., the boiling point of water in space is 160 F. or lower.

The control of the gas temperature within gas passages or unit S2 of heat exchanger 36 is accomplished by means of thermal bulb or sensor 100, which is located in heat exchanger 36 and is in good thermal contact with both the gas side unit 82 and the liquid side unit 84 of heat exchanger 36. Thermal bulb 100- causes shaft 102, projecting therefrom, to translate in response to temperature changes and thereby control steam outlet Valve 46 to control the pressure Within heat exchanger 36 and thereby the saturation pressure and temperature of the liquid therewithin and hence the boiling point of the liquid therewithin.

Referring to FIG. 8 We see thermal bulb or sensor 100 and translating shaft 102 projecting therefrom. Translating shaft 10-2 encounters piston member 104 and as temperature increases within heat exchanger 36 shaft 102 becomes extended from thermal sensor 100 and forces piston or valve 104 off valve seat 106 so that steam from steam exit header 58 may be discharged to space vacuum through ports 108. Spring 110, which projects between movable piston or valve member 104 and housing 112, brings piston or valve 104 back against seat 106 when thermal sensor 100 causes shaft 102 to retract when there is a temperature reduction in the heat exchanger 36.

As it is essential to have good heat transfer between thermal sensor 100 and the gas side unit 82 of heat exchanger 36, heat exchanger gas or oxygen passages or closure members 60 through 66 are sealed at one of their ends by closure channels such as 76, 'best shown in FIG. 6. Closure channel 76 includes elongated member 120', which is best shown in FIG. 5 to be channel shaped at its end, and circular member 122 which closely defines an accurately sized circular hole 124 which is machined to a high polish and with great accuracy so as to provide good thermal contact with the outer wall of sensor 100, which is also polished and accurately machined for this purpose. Circular member 122 is split at one end at split 126 and includes bolt holes 128 Which receive conventional bolts (not shown) for closing split 126 and thereby causing circular aperture 124 to firmly engage the outer wall of sensor 100.

To place the liquid side of the unit 84 of heat exchanger 36 in close thermal contact With thermal unit 100, wick sensors 130, best shown in FIG. 7, are provided. Wick sensors 130 extend through areas 86 through 94 and have a circular aperture 132 at one end thereof sized to snugly engage the outer surface of member 100. It has been found that sensor wick such as 130 can be accurately machined if the wicking material is saturated, then frozen, then machined.

Operation As the pressure suit occupant increases his metabolic activity level, more heat is transferred into the gas or oxygen stream. The transient heat load is transferred into the water boiler heat exchanger 36 and from the water boiler into the thermal sensor 100 which in turn controls a back-pressure valve which controls ythe saturation temperature and saturation pressure of the water side 82 of the heat exchanger 36. More particularly as the space suit occupant increases his activity level, he warms up the voxygen stream and this increase in temperature is transferred into the thermal bulb or thermal sensor 100 by the following means: The increased heat load is transferred into the thermal bulb through the parting sheets '70 and 72, lins 68 and closure channel 76. The 'primary mode of heat transfer is conduction.

To control the decreasing heatload case corresponding to a reduced metabolic output of the space suit occupant, the following mode of heat transfer takes place. The temperature of the gas or oxygen stream decreased caus-A ing less steam generation on the water side 84 of the heat exchanger 36 which in turn reduces the pressure on the water side for a particular valve position. The saturated wicks 'Which surround the thermal sensor 100 Will begin to boil to remain in equilibrium with the saturation pressure which wvill result in a subtraction of heat from the bulb 100 which causes the shaft y102 to retract and decreases the steam escape area in the valve. To summarize this, the thermal sensor is controlled for the increasing heat load condition by conduction and for the decreasing heat load condition by boiling water at the surface of the thermal bulb 100.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described but may Ibe used in other ways without departure from its spirit as defined by `the following claims.

We claim:

1. A pressure suit, a lift support system connected to provide gas to and extract gas from said suit, a gas-liquid heat exchanger forming part of said life support system, said heat exchanger including a gas passage system through which the suit gas is passed, a liquid reservoir in heat exchanger arrangement with said gas passage system and a steam exhaust system, and means responsive to the temperature of the gas extracted from said suit to regulate the pressure in said steam exhaust system and said liquid reservoir to control the boiling point of said liquid and hence the temperature differential between the liquid and gas to regulate the temperature of the gas provided to said suit.

2. Apparat-us according to claim 1 wherein said gas passage system comprises at least one sealed sandwich unit including top and bottom plate members with a corrugated sheet extending therebetween to form a plurality of parallel passages therewith and with closure members at opposite ends thereof.

3. Apparatus according to claim 2 wherein said liquid reservoir includes wicking material in contact with said gas passage system plate members and closure members and said wicking material being saturated lwith liquid.

4. Apparatus accordng .to claim 3 wherein said temperature responsive means includes a temperature sensor contacting at least one of said gas passage system closure members and said wicking.

5. Apparatus according to claim 4 and including a steam exhaust valve operatively connected to said temperature responsive means and communicating With said steam exhaust system and said liquid reservoir.

References Cited UNITED STATES PATENTS Potter et al. 62-259 X RICHARD A. GAUDET, Primary Examiner.

W. E. KAMM, Assistant Examiner,

UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No. 3,343,536 September 26, 1967 Edgar H. Brisson et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below tColumn 4, line 26, for "lift" read life same column 4, llne 49, for "accordng" read according Signed and sealed this 15th day of Octobel^ 1968.

(SEAL) Attest:

EDWARD I. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.

Attestng Officer 

1. A PRESSURE SUIT, A LIFT SUPPORT SYSTEM CONNECTED TO PROVIDE GAS TO AND EXTRACT GAS FROM SAID SUIT, A GAS-LIQUID HEAT EXCHANGER FORMING PART OF SAID LIFE SUPPORT SYSTEM, SAID HEAT EXCHANGER INCLUDING A GAS PASSAGE SYSTEM THROUGH WHICH THE SUIT GAS IS PASSED, A LIQUID RESERVOIR IN HEAT EXCHANGER ARRANGEMENT WITH SAID GAS PASSAGE SYSTEM AND A STEAM EXHAUST SYSTEM, AND MEANS RESPONSIVE TO THE TEMPERATURE OF THE GAS EXTRACTED FROM SAID SUIT 